The present invention relates to a device including a cutting device and at least one tear detector for cutting a web of paper in a press end of a paper machine, in response to a tear in the paper web in the dryer end.
In the manufacture of paper, the desire for maximum productivity is leading to plants with constantly higher production capacities and accordingly also to machines with constantly increasing speeds. The speed limits in this connection frequently arise from the drying section or the drying capacity available there, and from the danger of the paper web tearing. It is readily clear that forces which are not problematical at low speeds result, in the case of high-speed paper machines, in phenomena such as fluttering of the web and the like, as the result of which the web of paper may then tear.
Such tears of course cause a reduction in production. One particular problem in connection with such tears is that if the tear remains unnoted, the web of paper travels in a completely uncontrolled manner through the drying end. The drying end may become completely clogged to a greater or lesser extent, which may possibly require long periods of delay for the removal of the shreds of paper. Or, wrapping can occur, as a result of which the journals of the corresponding shaft may break. The dryer felts (dryer wires) of the drying end may also be destroyed.